Almost 150 NHS patients have been harmed by incidents that should never happen, according to new figures, including the wrong patient receiving heart surgery, patients given overdoses and one woman who had her fallopian tube removed instead of her appendix.
The incidents - called "never events" - are regarded by the Government as so serious they should never happen.
New figures from NHS England show there were 148 never events in the six months from April to September.
Overall, there were 69 cases where foreign objects were left inside patients, including 11 cases of surgical swabs, three cases where specimen retrieval bags were left inside, one patient who had wires left inside and another patient who was left with a needle in their body.
In one incident, a drill guide block was left inside the patient's body.
The figures also showed that 37 patients had the wrong part of their body operated on or treated.
This included four operations on the wrong tooth, an operation on the wrong toe, one patient who had an injection in the wrong eye and one case where a woman had the wrong fallopian tube removed during an ectopic pregnancy, probably rendering her infertile.
Another woman had a fallopian tube removed instead of her appendix.
Other details showed the wrong patient undergoing a heart procedure, and the wrong patient given an invasive colonoscopy to check their bowel.
In another case, the patient died as a result of failure to monitor their oxygen levels, while one woman died from heavy bleeding following a planned Caesarean section.
Another had the wrong type of gas given, resulting in the patient's death or severe harm, and one patient underwent surgery intended for someone else "due to incorrect results filed in notes".
Meanwhile, 21 patients were given the wrong implant or prosthesis.
Seven patients were given the wrong dose of chemotherapy, resulting in harm, and five died or suffered severe harm after feeding tubes were inserted incorrectly by NHS staff.
In more than five cases, patients were given overdoses of drugs, with a weekly dose given in a single day.
Other patients were given different overdoses, and there was one case of "maladministration of potassium-containing solutions causing death or severe harm".
Some NHS trusts had more never events than others, with Newcastle Upon Tyne Hospitals NHS Foundation Trust having the most at four.
This included two incidents where foreign objects were left inside patients, one patient who had a procedure on the wrong part of their body and one patient given the wrong type of implant.
Today's six-monthly figures are broadly comparable to last year's figures.
In the previous 12 months, there were 325 never events, suggesting this year's number could be similar.
Other hospitals with the highest number of never events included Gloucestershire Hospitals NHS Foundation Trust and Leeds Teaching Hospitals NHS Trust, which both had three.
Norfolk & Norwich University Hospitals NHS Foundation Trust also had three, as did Sheffield Teaching Hospitals NHS Foundation Trust and South Tees Hospitals NHS Foundation Trust.
The Royal Wolverhampton NHS Trust had three never events, as did University Hospitals of Morecambe Bay NHS Foundation Trust and West Middlesex University NHS Trust.
Overall, 102 NHS trusts had at least one never event between April and September this year, as did eight independent hospitals.
NHS England said the overall incidence rate is less than 0.005%, or one never event in every 20,000 NHS procedures.
Dr Mike Durkin, national director of patient safety at NHS England, said: "Awareness in the NHS of these issues has never been greater and the quality of our surgical procedures has never been better. It follows that the risk of these things happening has never been smaller.
"Every single never event puts patients at risk of harm which is avoidable. People who suffer severe harm because of mistakes can suffer serious physical and psychological effects for the rest of their lives, and that should never happen to anyone who seeks treatment from the NHS.
"But is time for some real openness and honesty. There are risks involved with all types of healthcare.
"And one of those risks - with the best will in the world and the best doctors, nurses and other healthcare professionals in the world - is that things can go wrong and mistakes can be made. This has always been the case, and it is true everywhere in the world."
A surgical safety taskforce is undertaking an in-depth review of surgical never events and is due to report in the new year.
NHS England said proposals will include standardising operating theatre procedure, and new standardised education and training.
Professor Don Berwick, who led a system-wide review of safety in the NHS, said: "No-one who works in any hospital wants to see patients come to any harm at all. When serious errors occur, it is a tragedy for both patients and staff, so the courage and commitment shown by the NHS in publishing this data are admirable.
"One way to help improve safety is by openly and honestly recognising, discussing and examining mistakes in care. That helps us create continually better systems and procedures.
"Blame and punishment have no productive role in the scientifically proper pursuit of safety. But openness and transparency do.
"They are the front door to learning and improvement. I applaud NHS England for this important step toward better knowledge and better support to both staff and patients."
Professor Norman Williams, president of the Royal College of Surgeons, also welcomed the publication.
He said: " Never events are incidents that are completely unacceptable. However rare these cases are, never should mean never, and avoiding such errors should be the priority of every surgeon.
"Together with NHS England, we have formed a taskforce which will look at ways to put an end to such errors. The group will be working with patients, individuals and organisations to learn from what has happened in the past to understand how to prevent them in the future."
Health Secretary Jeremy Hunt said: "We are determined to see the NHS become a world leader in patient safety - with a safety ethos and level of transparency that matches the airline industry.
"The publication of this data is a real step forward towards making this happen.
"In future, all hospitals will also have to publish ward-by-ward staffing levels, and a new national safety website will publish all the information relevant to safety in every hospital in the country on a monthly basis.
"We want the NHS to be more transparent than ever when it comes to safety. I expect hospitals to examine these figures closely and take action to make the right improvements."